refactor(repo): replace legacy openflare-server with Wavelet rename

Delete the old monolithic openflare-server implementation and rename
Wavelet/ to openflare-server/ to complete the migration consolidation.
Update CI workflows, agent Dockerfiles, and deployment docs for the new
layout (frontend/, docker/Dockerfile).

openflare-server/internal/apps/admin/push/constants.go

@@ -0,0 +1,15 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package push
+
+const (
+	channelCustom    = "custom"
+	channelEmail     = "email"
+	channelLark      = "lark"
+	channelTelegram  = "telegram"
+	defaultLevelInfo = "INFO"
+	keyTitle         = "title"
+	keyContent       = "content"
+	keyLevel         = "level"
+)